Can you add a second stormwater pit riser?

[JesseS6]

Hello,

I have a storm water pit in my backyard at a low point. The surface level still creates a significant dip in the yard. There is a 600 series everhard pit and a 600 series everhard pit riser. Is therre any issue with adding a second pit riser? or is this going to create an issue?

[JacobZ]

Hi @JesseS6,

Thank you for your question about the Everhard Industries Series 600 Stormwater Pits and their risers.

I've spoken with the team at Everhard, who have informed me that while it is physically possible, they don't usually recommend adding a second riser because each additional connection will create a weak point and increase the amount of inward pressure from the soil around it.

In saying this, if it is suitably installed with a concrete collar and reinforcing as mentioned in the Poylmer Rainwater, Stormwater Pits and Risers Installation Instructions, then the additional load should be held by the concrete and reinforcing around the pit.

Unfortunately, the only other option would be to lift and reinstall the pit and riser so that it is flush with the soil around it.

Let me know what you think and if you have further questions, please don't hesitate to ask.

Jacob

[JesseS6]

@JacobZ Hi,

When you say concrete collar, is this just around the top of the pit, or is it more of a culvert that the entire pit would sit in?

Also, this is just a domestic pit before the discharge point, can this be covered/buried? (dug up if needed)

[JacobZ]

Hi @JesseS6,

Upon review of the Poylmer Rainwater, Stormwater Pits and Risers Installation Instructions, I note that they have stated - 

"the National Plumbing and Drainage Code for stormwater drainage (AS/NZS 3500.3:2003) limits the maximum depth for stormwater and inlet pits...

600x600 pits should not be deeper than 900mm to outlet invert"

Apologies, I missed this in my first look through. If you were to add a second riser, the depth would exceed the 900mm set out by the plumbing and drainage code.

I'd suggest it would be best to speak with a plumber about any alterations to your stormwater system to ensure you are compliant with the relevant codes and regulations.

Jacob